It was a quality bicycle for the year 1919, and an odd one as well: bright green, with an upturned green handlebar, a fancy-for-then coaster brake and a broad, huge-springed­ leather Brooks saddle. For many of the nine years that 34-year-old Ronald Light had owned the bike, he'd ridden it daily and, now, thinking back on his story, I can imagine Light rolling the bike out of Leicester, England, the booming industrial city where he lived, and into the quiet countryside, the breeze riffling his knit golf cap and necktie as he pedaled through the gentle hills of the British midlands, past small peasant cottages and little stone churches and pubs and green grassy meadows lined with hedgerows of hawthorn, blackthorn and ivy.

Blandly handsome and lean, with short, brown hair, a narrow, beaklike nose and a placid manner, Light was a wealthy one-time Army officer who had returned from World War I shell-shocked and disgraced. He'd been court-martialed for forging telegraphs, and ended up in Leicester unemployed and living with his sickly mother. Cycling was his escape.

But in the 9 p.m. darkness of this cold night in late autumn, Light was not riding but pushing his bike through the still streets of Leicester and, I suspect, desperately hoping no one would hear the low, grinding noise his machine gave off as the loose back wheel scraped the frame.

About five months earlier, in July 1919, a fetching young factory worker, Bella Wright, had been fatally shot in the head while riding a rickety bicycle outside of Leicester. The last person with whom she was seen was a new acquaintance: an unshaven man on a green bicycle. The name of this man was originally a mystery but it is now one of the few facts about the case everyone can agree on: It was Ronald Light who rode with Bella that night. The principle question is what happened that languid summer evening after they began rolling east over the crushed-stone roadways into the village of Gaulby.

Police investigators contended that Light shot the young woman with an Army-issue revolver, and his trial for her murder in early 1920 became a courtroom spectacle that was essentially the O.J. trial of its day. Facing a sentence of hanging if convicted, Light won his freedom by arguing, with refined, public-school poise, that he was an innocent man unjustly tangled in a sordid affair.

Had Light ridden with Bella that night? Oh yes, he assured the jury. He had indeed. But had he, to quote his lawyer, Sir Edward Marshall Hall, "shot this unfortunate creature?"

"Certainly not," proclaimed Ronald Light.

Until taking the stand, though, Light hadn't acted innocent. In the weeks following Bella's death, as "wanted" posters describing the still-unidentified suspect went up on telegraph poles throughout Leicester, Light hid his beloved bike in a closet. He said that, though he'd done nothing wrong, he didn't want to go public as the man on the green bicycle; he was afraid, he would explain in court, of worrying his mother. "She's been under the doctor for many years," he said. "She has a bad heart."

At some point, Light decided to rid himself of the bike altogether, and that's how he found himself one cold night trudging through serpentine streets laid down almost two millennia earlier by the Romans who founded the city. He passed through the ancient kingdom of King Leir, Shakespeare's inspiration, and snuck along among crumbling baths, walls and aqueducts. He descended some stairs to the bank of the River Soar.

Soon, a laborer named Samuel Holland, en route to the graveyard shift at a nearby mill, spotted a man beside the Upperton Road bridge, stooped over a bicycle frame and visible in the yellow pool cast from the bike's lamps. As Holland watched, the man stood up, then strode a few yards down the path and, piece by piece, began throwing the bicycle into the water. The frame, the crank, the wheels, the pedals--everything went down into the murk.

It is now February 2007 and I'm standing by the Upperton Road bridge myself. I've traveled here, 6,000 miles from my home in Oregon, because ever since a random Google search coughed the details of the Green Bicycle Murder up onto my screen, it has intrigued me.

It may well be history's most famous bike-related killing. Six thousand people came to Bella Wright's funeral, and when Light was tried, newspapers all over England went yellow with thrill. "Who murdered Bella Wright?" blared the Daily Express in a multideck page headline that continued, "Green bicycle clue in lonely lane crime."

"Grim story of a raven," quoth the Daily Sketch, electing to focus on a black bird that was mysteriously--and quite gothically--found dead beside Bella's body.

The affair also appealed to me because of its antique splendor, coming as it did in the last era when a bicycle could sit at the center of a cultural uproar. Bella was killed just as the joys of cycling, which for so long had been reserved for the well-heeled, were trickling down to the masses, who could suddenly afford a decent used ride, replete with mudguards for a few weeks' wages. Automobiles were not yet widespread, so on those rough roads, factory­ workers, coal miners and farmers moved as quickly as kings. Society was changing: Peasant families who had clung to their own villages, inbreeding for centuries, now mingled with faraway visitors and expanded the gene pool. To facilitate pedaling, ladies began wearing bloomers, casting off their heavy dresses--and, some historians say, striking the first spark for equal rights.

But what drove me toward Bella and Light, ultimately, was a book. The Green Bicycle Murder, written in 1993 by the British author C. Wendy East, is the most celebrated work on the case and it was, in my view, unsatisfactory. East is coolly reasoned in the book, but her arguments are founded on a dubious premise: "I never doubted Light was guilty," she told me when she and I spoke briefly.

"But how can you know," I asked, "unless you have, like, a videotape?"

"There is a way of knowing," East said cryptically.

Her portrait of Light is peevish, dismissive. In discussing his war experience, for instance, East says, "His company seems not to have come under either long or continuous fire in France," and notes that Lieutenant Light was likely pampered with frequent food parcels from home. Her book has largely shaped public opinion. Today, most people who know anything at all about Light--who died in 1975 at age 89--regard him as a spoiled brat who got away with murder.

There is no doubt Light grew up privileged. His father was a successful inventor of plumbing devices. The family had servants and, at one point, lived in an elegantly spired Leicester town house replete with a third-story balcony that yielded a view of the horse races at nearby Victoria Park.

There's also no lack of proof that Light was a troubled character. In 1902, at age 17, he was expelled from the elite Oakham School for "lifting a little girl's clothes over her head," according to a brief filed by prosecutors in the murder trial. In his 30s, he "attempted to make love to a girl 15 years of age," according to the same brief, and admitted to "improper conduct" with another young girl, this one a mere eight years old. Two girls, ages 12 and 14, even testified in court that early on July 5, 1919, just hours before Bella's murder, Light had chased after them as they wended their bikes through the countryside.

My initial research led me to imagine Light as slimy and despicable--wearing a trench coat, perhaps, as he hunches nervously over his strange handlebar, his teeth idly gnawing at the air, like a ferret's, as his face bears a beady-eyed intensity. But all accounts depict him as calm and well-spoken in court, and in extant photos he appears almost blank-faced, as though no turgid thoughts whatsoever churned through his skull. Still, one photo lingers in my mind. Taken just a day or so after he was acquitted, it captures Light in a double-breasted suit and a tie held neatly in place by a pin. He is staring at the camera, his lips slightly pursed, his head tilted a bit, his eyes fixed straight ahead. He seems to be saying, as always, "Everything's normal here. Nothing is wrong." But in this picture there's an undertow of determination in his look--the slightest hint of how hard he is working to conceal the secret that everything is wrong.

Light was an only child. He was smart. He got decent grades and seemed suited to step into the life of privilege presented to him by his father, a self-made man born to working-class parents. But as it turned out, his life was a series of disappointments. He lost his job at the railway in 1914 after he was suspected of setting a fire in a cupboard, and of drawing indecent figures on a lavatory wall. Later, working at a farm, he was accused of burning haystacks and dismissed. By the time Light was axed from his post as an Army second lieutenant in 1916, his father had fallen out of a second-story window in his home early one morning and died--an apparent suicide. Light's mother told police, "For the past few weeks, he has been worried a good deal about our son."

Light reenlisted, this time as a gunner, and when he came home after several months amid screaming howitzers on the Western Front in France, he was partially deaf. He'd seen fellow troops die or be wounded almost daily, as England had lost nearly a million soldiers in a conflict that, in the end, brought only despair to the country. "If any question why we died," wrote the poet Rudyard Kipling, "tell them because our fathers lied."

It's my sense that Light carried a certain grim nihilism. But did this make him a murderer? I couldn't say.

I thought if I traveled to the scene of the crime I might attain a definitive verdict. But the Leicester of 1919 is largely buried beneath a new, vibrant city of 285,000. The stone church in which the poet Geoffrey Chaucer was married, in about 1366, is still there, as is the 287-year-old Globe pub, which faithfully serves 13 varieties of Real British Ale. Mostly, though, contemporary Leicester is a multicultural experience. It's currently poised to become Britain's first white-minority city, and emigrant Somalis, Ugandans, ­Pakistanis and Bosnians coexist here in relative peace. One evening I found myself in a launderette eating Indian takeout as I chatted with a pale young hipster intent on making a film about zombies.

Bella Wright seemed quite far away--even as I made my way along the towpath, past a bramble of high, tawny weeds toward St. Mary's Mill, the looming brick building in which Bella last worked at her job making bicycle tires for W&A Bates. The building is now divided into several smaller business spaces, and the first person I encountered--a sullen young man of 30 or so--worked for a concern that made inflatable castles. He wore a blue tracksuit and his ears were bejeweled with gold earrings as he squatted there, rolling a cigarette. I told him of my mission and then asked if he knew anything of Bella Wright.

"No idea, mate," he said. "I don't got the foggiest, and it doesn't mean fuck all to me."

On the evening of Saturday, July 5, 1919, Light spun north out of the village of Great Glen, through a region known as the Strettons. He passed fields of stubble turnip and beet, and at about 6:45 he spotted a young girl stopped by the roadside, bent low as she inspected a wheel. Bella Wright was 5-foot-2, with what the police called a "well-nourished figure." Her hair was auburn, her eyes soft brown, and she looked up at Light from beneath the black felt rim of her hat. There was some play in her freewheel. Did Light have a wrench?

He did not, but he did offer to accompany her. They rode east, down a hill toward the village of Gaulby, where Bella planned to visit her uncle and deliver a gift of some gorse.

While Light would claim in court that Bella was a stranger to him, there is some evidence to the contrary. Bella's mother, Mary Wright, would testify that, in early 1919, "Bella came home after a ride on her bike and said, 'What do you think? When I went down Braunstone Lane, I had an officer fall in love with me.'"

It's safe to assume that Bella did not traffic often with officers. Her father, a cow herder, was illiterate. She was the oldest of seven children, and the family lived 4 miles outside Leicester, in the village of Stoughton, under essentially feudal conditions. Their tiny cottage sported a thatched roof and porous walls that wept profusely during wet weather. The floors sagged, the oak beams were bowed, and the outhouse sat a good distance away, by the animal barn.

Still, Bella was no numbskull serf. Rather, she emerges from the legal papers as a self-possessed, forward-thinking young woman. After she finished school at age 12, she took the standard route for girls of her station and worked as a domestic servant. Soon, she saw that there was better pay--and hence more freedom--in factory work, and began pedaling to her night shift at Bates, alone over the dark, hilly 5-mile route. On weekends, ­according to the Leicester Mercury, "She was often to be seen riding alone. She was never really happy except when enjoying the pleasures of the country-side." She fixed her own flats, using tubes she got almost gratis at work, and though she was, in the parlance of the day, "keeping company" with 18-year-old Archie Ward, a stoker away at sea on a Royal Navy steamship, she still lived as she wished. Just one week before her death, on June 28, she'd gone to a party with her workmates and allowed a young blacksmith, William Wood, to escort her home through the night.

Did Bella see in Ronald Light a beguiling and urbane older man? Perhaps. In telling her mother of her encounter with the "officer," Bella recounted, "He asked me who I was, and I told him I was a labouring man's daughter. He said what a nice girl I was and said by my nice ways and looks I ought to be in a nicer position than a labourer's daughter."

They rode, Bella and Light, down the hill. Then they started up another and hopped off, walking side by side. While Bella stopped in at her uncle George Measure's cottage, Light waited for her, passing time in the village by, he claimed, attending to a flat tire. Bella's uncle told her he didn't like the look of her scraggly cycling partner, who lingered outside, unshaven and wearing a raincoat on a clear night.

But when Bella emerged after an hour inside, she rejoined Light and the two of them rode west out of Gaulby, into the midsummer twilight, at about 8:50 p.m. Thirty minutes later, a farmer would find her on an ancient Roman thoroughfare, the Via Devana, lying dead in a puddle of blood.

I wanted to see the terrain Bella rode on her last night alive, so I rented a bike one cold, sleety morning and rode off toward the Strettons with a man named Philip Draycott.

Draycott, 59, is a college professor and TV film director, and the Falstaffian soul of a leisurely cycling club, the Leicester Spokes, who meet each Wednesday night for a spin of 20 miles or so before ending their ride at a pub.

Draycott is amply built for a cyclist, and as we set out, weaving through traffic, he wore a fluorescent yellow vest and fulminated with brio at motorists. "Indicate," he yelled at a guy who turned without signaling. "Indicate!"

We turned right onto the Via Devana, and then pedaled by a few World War II bomb shelters crumbling into the farm fields. Soon, we passed a little cottage that was selling for $800,000, and I began to see that these days the Strettons are inhabited not by rustics but by people of means enchanted with the idea of rusticity. At Bella Wright's former home, rechristened Sandbank Cottage, a Jaguar sat in the drive.

We passed the village of Little Stretton and then came to a gentle uphill, roughly paved, bordered by looming oak and ash trees, and shadowed by their high, spindly branches. The road's dotted white line climbed into the gray distance. Here was where Bella Wright died.

"This very hill!" Draycott intoned with mock tour-guide solemnity. Then he laid out the geography of the case against Light. About a mile west of Gaulby, he said, Bella fled Light and his unwelcome advances. Panicking, she detoured south, setting out for home on a route that was not only longer--4 miles instead of 3--but also obstructed in two places by cattle gates. As Bella labored along, Light whipped down Gaulby Lane, then eventually cut over to intersect Via Devana, where he lay in wait by one of the cattle gates. He shot her, said Draycott, then fled down the gated path before us, escaping through the gathering dusk.

To test Draycott's theory, I began riding over the path on my own bike, through spitting snow. The mud was ankle-deep, and it sucked so hard at my knobby tires that after 30 feet I shuddered to a stop, then stood gazing into the distance at the spire of the church in Stoughton, where Bella once played the organ on Sundays. But my mind kept turning back to the rusty field gate, which was now quietly piling with snow.

"I found smears of blood on the top bar of the field gate," police constable Alfred Hall wrote in filing the only on-site account of the Green Bicycle Murder. "I made a diligent search for footprints but could find none [on] either side of the gate."

Hall searched for hours, driven by his conscience. The doctor who'd come to the scene to examine Bella's corpse was shockingly cursory. Giving the body a quick once-over, by candlelight, he opined that Bella had simply crashed to her death--an accident.

Spooked by Bella's blood-spattered body, Hall went home and fretted over this summation until, at 6 the next morning, he rushed back to the crime scene and unearthed a .455 bullet buried in the dust 17 feet from where Bella still lay. He washed the dead girl's face, and found, he later wrote, "a bullet hole about one inch behind and half an inch below the left eye."

Hall's court testimony was no less dramatic. He declared that the blood on the gate had come from a dead raven found at the scene, and that it had died from "gorging itself on blood." Indeed, Hall claimed, citing footprints, that raven had made six gruesome, bloodthirsty journeys between the gate and the corpse.

There are no ravens in the midlands of England.

When I called Kevin McGowan, a crow specialist at the Cornell Lab of ­Ornithology, he was doubtful that a look-alike bird--a crow or a rook--would or could gorge on human blood. "These birds don't have lips," he explained. "They can't get enough suction to suck blood."

To my mind, the raven--or whatever it was--is evidence only of how the Green Bicycle Murder haunted the imagination back in 1919. It wasn't just a story about a girl being killed. It was also about a certain hope dying. As David Hughes, a law professor at Leicester's De Montfort University, wisely told me, "In 1919, with the war just over, people were desperately trying to get back to normal and Bella--she was poised to be married to a sailor. She and Archie Ward were going to be building the nation again, and suddenly she's killed."

But the raven was only one of the eerie, powerful images that floated through all the stories being told about the murder. On Febuary 23, 1920, a man named Enoch Whitehouse was hauling a load of coal along the River Soar, on a boat drawn by two horses dutifully plying the towpath. Near the Upperton Road bridge, his towrope went slack, dipping into the brown, filthy water. When it emerged, there was a green bicycle frame tangled up in it.

Soon, several constables lined the banks, wielding lawn rakes and dangling hooks, combing the canal for evidence. Detectives scrutinized the green bicycle. It was mutilated: Someone had filed the brand name, British Small Arms, off the fork and also scraped the serial number off the seat lug. The cops called in a bike mechanic who was able to locate a faintly visible second serial number inside the front fork--103648. Ronald Light had bought a BSA bike with that serial number in the city of Derby on May 18, 1910.

In his largely forgotten 1930 book, The Green Bicycle Case, H.R. Wakefield exudes a chummy Old Boy's regard for Light and suggests that his clandestine manner was not guilt-induced, but rather the "very human" behavior of an innocent man under stress. As he rolled his bike toward the canal, Wakefield reckons, "Light may have said to himself: 'I am doing no harm, there is nothing I can say which could contribute toward the solution of the mystery. But to come forward and face the frightful blaze of publicity, probably to be arrested, and have to stand my trial. Cui bono?'"

The policemen of Leicester were not inclined toward such florid Latin. On March 4, they yanked Light out of Dean Close School, a boy's academy where he'd just begun teaching math. "I never had a green bicycle," he swore.

The cops tossed him into the jail in Leicester. Fifteen days later, a police sergeant dredged an Army gun holster and 12 live .455 caliber bullets out of the canal. The bullets precisely matched the one that Alfred Hall had found. Sequestered in his cell, Light hissed to himself in a fury: "Damn and blast that canal."

Before I really learned about him, I assumed that the polished, privileged Light was a villain as hated by the general public as, say, the suave serial killer Ted Bundy. I guessed that England's long-ago proletariat rejoiced in Light's arrest and hankered to see him swing from the gallows. What I didn't realize was that the Brits' enchantment with aristocracy--evidenced even now by the widespread working-class love of the royals--was even thicker just after World War I. The glorious British empire was fast fading, and upper-class youths who'd risked their lives to defend it by fighting in World War I were seen as consummate noblemen.

Though the press coverage was sensational, Light's despicable past never made it into print, and the stories about him were nearly all sympathetic. In one front-page headline, for instance, the Leicester Mercury fretted over "Ronald Light's Ordeal." The subheads read, "Why he did not come forward. Feared 'unpleasant publicity.' Didn't want to worry his mother." As Bella was reduced to a mere "factory girl," Light was honored in print as an "engineer, teacher and ex-Army officer."

Light's trial, which drew an overflow crowd of friendly gawkers, was set in Leicester Castle, a grand, turreted complex built in the 1060s by the Normans, with Sir Thomas Horridge presiding as judge in a white-powdered wig. The star of the drama was not Light but his barrister--Sir Edward Marshall Hall, who was the Johnny Cochran of his day. Then 61, Hall had made a career of helping wealthy suspects triumph over formidable and sordid murder charges--the killing of a prostitute or of a young mistress. Glib, handsome and 6-foot-3, he was a master of oratory--and restraint. He did not cross-examine Bella's mother or uncle, or even stop Light from admitting that he once had a revolver and that the holster dredged up from the canal was his. Hall saved his haughty disdain for the prosecution's ballistics expert, a Leicester gunsmith named Henry Clarke.

In a prolonged browbeating, Hall got Clarke to concede that there were scratch marks on the bullet found near Bella's body. "This bullet could be from a rifle as well as a revolver?" Hall asked meaningfully.

"Yes," admitted Clarke.

Hall then posited that maybe the fatal shot had been accidentally fired from "some distance away." If Bella had been shot at close range, as would be necessary with Light's revolver, Hall continued, wouldn't it almost "blow the side of the head off?"

Listening, Light canted forward in his seat, clutching the bench before him with stiff, clawlike hands. He looks boylike in the newspaper photos--almost fragile in his neat white shirt and tie. When, after three hours of deliberation, the jury declared him "Not guilty," he collapsed for a moment. A joyous horde closed in on him, crying, "Well done, Light!" and "Good old Light!" Then the free man slipped out of the castle and took the tram home across town, alone and unnoticed.

In the years after his trial, Light all but vanished. While researching her book, East established that by 1928 he'd moved to the village of Leysdown, on Island of Sheppey, in Kent--a seaside holiday spot for Londoners. Visitors go there in droves, making it easy for a person to hide in the ever-changing crowd. Light lived for a time under an assumed name, Leonard Estelle. He married an older woman with a daughter, but fathered no children himself, and it seems that East could not even ascertain if he ever worked. Over the phone, East told me, "When he died, his stepdaughter had never even heard of his trial." In Leysdown, he was remembered, she writes, "as an elderly balding man?who was often seen leaning on the gate of his cottage smoking a cigarette and watching the world go by."

I wanted more details, so I made calls to Kent--to newspapers, to the police and to the public archives. I found nothing, not even an obit. The lawyers who helped Hall prep a defense destroyed their papers right after the trial. Most of the police records for 1919 are missing. The bullets and holsters dredged up from the canal are in the hands of an anonymous collector who bought them for $6,000 at Christie's in 1987. Even the green bicycle itself, which for several decades hung on the wall of a local bike shop, has been lost.

Little remains but speculation.

One morning, I met with Ben Beazley, a retired police officer who has written several books on the history of Leicester. He hypothesized that Bella was killed not by Light but by a love interest in her own social circle. The evidence, he suggested, lay in a rather unfortunate line from the prosecution brief: Though Bella had not been raped or forcibly molested, the document said, "The girl was not a virgin."

A retired clerical worker named Alison Keay had her own theory. A soft-spoken and painfully shy criminology buff who loves the TV program CSI: Las Vegas, Keay fixated on the bullet entry wound in Bella's cheek, which, according to court records, was just large enough to "admit an ordinary pencil." To Keay, such a hole seemed small for the dusty .455 bullet found near the corpse. After she found a self-appointed ballistics expert on the Internet, a retired American police officer named Dave, and Dave confirmed her hunch. Then Keay self-published a 60-page treatise, "The Green Bicycle Murder and New Evidence." It posits that Light was innocent and that the dusty bullet and the look-alike bullets the cops found in the canal were "complete red herrings." She may be right on this point. But her book lacks a theory as to who did kill Bella, and why.

Keay says she's still mulling over those questions. "It was definitely a cover-up," she told me. "The police knew more than they let on. Bella might have seen something she shouldn't have seen, like maybe some military exercises, some enemy training."

I pointed out that by 1919 World War I had ended, but Keay persisted. "Say like a German plane came over," she said. "They practice on random targets, don't they? And there was a raven, wasn't there--a black bird? The bird has something to do with it. I'm just not exactly sure what yet."

Eventually I found my way to law professor David Hughes. Sixtyish and rotund, with a grand thespian air, Hughes is arguably the premier expert on the Green Bicycle Murder. He recently directed a mock trial of Light, and he possesses a keen radar for the case's nuanced class ramifications; the grandson of domestic servants, he is also a graduate of Cambridge University.

I met him on a snowy morning in his office, which was absurdly cluttered with books and appointed with throw rugs. Hughes was wearing a cream-colored waistcoat, a green Cambridge country tie, and a large copper coin, a George IV farthing, on a long watch chain. "Do come in," he beckoned. He quickly dismissed one theory I'd heard--that the Freemasons orchestrated Light's acquittal--calling it "that old canard," before dismantling it.

For Hughes, the soul of the case lies in a philosophical question. "Why does crime happen?" he thundered. "To quote the great Cambridge criminologist Sir Leon Radzinowicz: opportunity. Let's say that Light had a fantasy about young women--and clearly I think he did. On that night, along came Bella. At some point, she saw his hunger. She fled."

Slowly and rhythmically, Hughes began spinning his hands above his prodigious belly to imitate a spinning bicycle crank. "And now," Hughes said, "Bella's coming along, down the Via Devana, on a rattly old bicycle with a defective wheel. She's weaving along--and suddenly out from behind the hedge steps the very man she's been trying to avoid. She tries to turn 180 degrees, to get away from him--"

Hughes was now madly spinning his hands, and we were both watching them spin, transfixed. "And she panics," he said. "She turns the bicycle over! She's on the floor, and Ronald Light--suddenly he's standing above her, dominant. He has attained his fantasy. He holds the ultimate power, which is not about sex but about destroying. He can kill her!"

Hughes' hands were dead still. He looked at me, somber and wide-eyed. "And that is what Ronald Light did," he said. "He murdered the girl."

When I returned home from England, I believed that Hughes's story was as close to the truth as anything I'd ever find. Then one afternoon I received a final batch of legal papers from Leicestershire County Records. I sat out on my porch, reading through legal boilerplates, nothing surprising--until one document stunned me. Drafted by Levi Bowley, the superintendent of the Leicester Police, three days after Light's acquittal, it described how Light had come back to retrieve the personal items that had been seized from him upon his arrest. Bowley said that, because he'd treated Light well in prison, they were on good terms; they talked in his office and Light said: "Well, you are a good sport, if I tell you something can I depend on you keeping it to yourself?"

Bowley said yes, then Light responded "Well, I'll tell you, but mind it must be strictly confidential, no other person knows about it and if you divulge it I shall, of course, say I never told you anything of the kind." Then, Bowley wrote, Light volunteered this confession:

"I did shoot the girl but it was completely accidental, we were riding quietly along, I was telling her about the War and my experience in France, I had my revolver in my raincoat pocket and we dismounted for her to look at it. I had fired off some shots in the afternoon for practice and I had no idea there was a loaded cartridge in it. We were both standing up by the sides of our bicycles.…I took the revolver from my coat pocket and was in the act of handing it to her, I am not sure whether she actually took hold of it or not, but her hand was out to take it when it went off. She fell and never stirred, I was horror struck, I did not know what to do, I knew she was dead, I did not touch her, I was frightened and altogether unnerved and I got on my bicycle and rode away."

Not one of the hundreds of news stories I'd read mentioned this confession and, instantly, I doubted its authenticity. While all the other documents in the file bore murky, dark type, this one was faint, with even type strokes. Was it a planted fraud intended to put the mystery to rest? Or someone's idea of a practical joke--a hoax?

Robin Jenkins, the keeper of the Leicestershire Archives, guessed that the document was legitimate. Bowley's report, he told me, "was secret until the Leicester Police deposited it with us just eight or 10 years ago."

I tracked down Philip Bouffard, an Ohio-based forensic document specialist who is arguably the expert on historic typography. In 2004, the New York Times turned to him as it analyzed 1970s-era papers relating to George W. Bush's National Guard stint. Bouffard was suspicious about the type. "This document is typed at 12 characters per inch," he said. "It's monotone elite, and in the 1920s most things were pica elite--10 characters per inch. And I can't get over how crisp and sharp the letters are. The alignment is very good. On a 1920 typewriter, you'd typically have a lot of letters off to the left or right a bit, or off up and down. Something's not right here."

I consulted another typography expert, Harry C. Pears, who lives in Australia and graciously agreed to scrutinize a host of '20s-era typefaces for me. He wrote back to say, "I can find very little evidence that the report wasn't created in the 1920s." He speculated that it was made on an Underwood typewriter.

But of course, neither of these assessments proved much at all. I knew that Bowley himself could have drafted a bogus report, just for kicks. For that matter, if I really wanted to spend the dough, I could go out and buy an ancient Underwood typewriter then type up my own confession on yellowing paper and slip that into the files. In the end, I kept circling back to something Wendy East had told me when I asked for her take on Light's confession: "I think you must make of it what you will."

History demands that of us--a little interpretation, I mean, a little bit of connecting the dots. It's a matter of taking the still, dusty past and reinventing it so that it becomes, suddenly, a story, a cinematic drama that we can believe in. And the more the dust settles on the past--the more the old documents get lost and the principals wither away and die--the more the whole enterprise of writing history becomes conjectural.

It's easy now for me to see Ronald Light swooping around the corner onto the Via Devana at dusk, his revolver tucked in his trousers, jolting heavily against the bone of his hip as he rattles over the rocks on the road. It's easy to imagine the sick, hot hunger that frothed in his breast as he lay in the grass, watching Bella emerge through the hedgerow. She's panicked and flushed--­enchanting in the soft evening light...

And then the film flickers out. The house lights click on, and all we have in the end is Ronald Light stooped by the gate of his home with a cigarette. All we know is what we can see: that Light is old, and his face has become wrinkled and ancient--eaten away by time, and by whatever worries and self-­reproach he harbored deep in his conscience.